Year: 2019
Type: article
Abstract: A deceptively simple quantity, the thermoelectric figure of merit $Z\phantom{\rule{0}{0ex}}T$ measures how efficiently a conducting material develops a voltage under a temperature gradient. Its key ingredients are thermopower S and lattice thermal conductivity ${\ensuremath{\kappa}}_{l}$: if the latter were zero, $Z\phantom{\rule{0}{0ex}}T$ would simply equal ${S}^{2}$ in units of the Lorenz number. This paper shows that the layered perovskite La${}_{2}$Ti${}_{2}$O${}_{7}$ is not far from this ideal: it has large $S$ due to a rapidly rising density of states typical of transition metal cations, and very small (for a crystal, anyway) ${\ensuremath{\kappa}}_{l}$ due to its layered structure: a feature expected in any material in this class. Along with a Goldilocks combination of large electrical conductivity and modest electron thermal conductivity, this leads to a ''colossal'' figure of merit over twice that of most current materials.
Source: Physical Review Materials
Authors: Vincenzo Fiorentini, Roberta Farris, Edoardo Argiolas, Maria Barbara Maccioni
Institution: University of Cagliari
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2949182425